Designing and patterning inorganic materials with porous and complex shape is a central theme in engineered material science. Several routes of “morphosynthesis” and templated, inorganic materials synthesis have been reported. Diverse underlying principles of these routes include, for example, block copolymer mesophases, colloidal arrays, bacterial superstructures, replication via reverse micelles, bicontinuous microemulsions, oil in water droplets, and emulsion foams.
Highly ordered, surfactant templated porous silica structures (e.g., MCM-41) structures consisting of bundles of hexagonally close-packed cylindrical channels are disclosed in “Ordered Mesoporous Molecular Sieves Synthesized by a Liquid Crystal Template Mechanism,” by C. T. Kresge et al., Nature 359: 710 (1992). A similar structure with tunable pore diameter and “thicker” pore walls (e.g., SBA-15) is disclosed by D. Zhao et al. in “Triblock Copolymer Synthesis of Mesoporous Silica with Periodic 50 to 300 Angstrom Pores,” Science 279: 548 (1998). These materials are both based on tetraethylorthosilicate (“TEOS”).
It is known that oriented organization of pores may result in higher selectivity with respect to catalytic applications, thus increasing their efficiency, especially in water/steam and high temperature catalytic applications. Such harsh conditions, however, may result in the collapse of the rather thin silica pore walls, minimizing the organization of the pores and reducing pore volume with a concomitant reduction in catalyst activity. To date, MCM-41 and SBA-15 type and similar materials have not been extensively utilized as industrial catalyst or catalyst support materials.
There thus exists an ongoing need for robust siliceous materials having tunable pore structures. Such materials would be particularly beneficial as industrial catalysts and catalyst support materials, heavy metal remediation materials, antibacterial materials, sorbents, pigments, and high temperature air pollution control applications.